Endometriosis is an oestrogen-dependent inflammatory disease affecting menstruating women, with varying levels of severity. Oestrogen dysregulation is responsible for chronic inflammation, angiogenesis, endometrial lesion development, progression, and infertility during menarche in afflicted women. The inflammatory mediators associated with this chronic painful disease have been established, with research also indicating the relationship between dysbiosis and disease manifestation. Endometriosis is also present with several painful comorbidities, including endometrial cancer, cardiovascular disease, and autoimmunity. The lack of specific and sensitive non-invasive diagnostic procedures, coupled with poor response to current therapeutic approaches, means that treatment needs remain unmet. Surgical procedures are performed to remove endometriosis ectopic lesions, for which the recurrence rate of disease is up to 50%, with certain patients exhibiting no alleviation of symptoms. This review aims to outline the aetiology of endometriosis, detailing novel diagnostic approaches and potential therapeutic approaches, namely advanced therapeutic medical products (ATMPs), including stem cell therapy and clustered regularly interspaced short palindromic repeats (CRISPR) gene editing. This timely review also provides novel insights into the important recent modalities which may be applied for the diagnosis and therapeutic response of endometriosis, including biomarkers, microfluidic platforms, and organoid systems. Undoubtedly, reliable, reproducible, sensitive, and specific models of endometriosis in humans are urgently needed to investigate and detail the aetiology of this debilitating disease.